742 Chapter 14 Files and Streams
14.12 (Telephone-Number Word Generator) Standard telephone keypads contain the digits area through through nine. The numbers two through nine each have three letters associated with them (Fig. 14.43). Many people find it difficult to memorize phone numbers. so they use the correspon¬dence between digits and letters to develop seven-letter words that correspond to their phone mute bers. For example, a person whose telephone number is 686-2377 might use the correspondence indicated in Fig. 14.43 to develop the seven,letter word "NUMBERS." Every seven-letter word car-responds to exactly one seven-digit telephone number. A restaurant wishing to increase its takeout business could surely do so with the number 825-3688 (i.e., "TAKEOUT").
Every seven-letter phone number corresponds to many different seven-letter words. Unforte. nately, most of these words represent unrecognizable juxtapositions of letters. It is possible, how¬ever, that the owner of a barbershop would be pleased to know that the shop's telephone number, 424-7288, corresponds to "HAIRCUT." The owner of a liquor store would, no doubt. be delighted to find that the store's number. 233-7226, corresponds to "BEERCAN." A veterinarian with the phone number 738-2273 would be pleased to know that the number corresponds to the letters "PETCARE." An automotive dealership would be pleased to know that the dealership num¬ber, 639-2277, corresponds to "NEWCARS."
Write a program that, given a seven-digit number, uses a PrintStream object to write to a file every possible seven-letter word combination corresponding to that number. There are 2.187 (3') such combinations. Avoid phone numbers with the digits 0 and
at 13 (Student Poll) Figure 7.8 contains an array of survey responses that is hard coded into ill program. Suppose we wish to process survey results that are stored in a file. This exercise minim two separate programs. First, create an application that prompts the user for survey responses and outputs each response to a file. Use a Formatter to create a file called numbers.txt. Each integer should be written using method format. Then modify the program in Fig. 7.8 to read the survey responses from numbers . txt. The responses should be read from the file by using a Scanner. Meth¬od nextint should be used to input one integer at a time from the file. The program should con tinue to read responses until it reaches the end of file. The results should be output to the text file "output .txt".
Modify Exercise 1 1 . 18 to allow the user to save a drawing into a file or load a priordrawin& from a file using object serialization. Add buttons Load (to read objects from a file), Save (to write objects to a file) and Generate Shapes (to display a random set of shapes on the screen). Use an ObjectOutputStream to write to the file and an ObjectinputStream to read from the file, Write the array of MyShape objects using method writeObject (class ObjectOutputSt ream), and read the array
